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Objectives. Twin to twin transfusion syndrome (TTTS) is one of the most important problems for perinatal management of monochorionic twins. Since TTTS is deeply related to the prognoses of both fetuses, fetal circulation and placental blood flow of monochorionic twins were studied with the purpose of clarifying characteristic features.Methods. The patterns and numbers of vascular anastomoses were checked on the placental surface, arterio-arterial (A-A) anastomosed vessels by ultrasound, and circulatory changes were studied with relation to uterine contraction.Results. The high risk of monochorionic twin pregnancies was largely related to the patterns of vascular anatomy of the placenta and numbers of anastomosed vessels. The first placental vascular connection detected in vivo was the A-A anastomosis characterized by the bidirectional flow waveform in pulsed Doppler velocimetry.Conclusion. TTTS is related to anastomosed vessels on the surface of placenta. To manage and prevent TTTS, fetal circulation and placental blood flow should be carefully observed. [ABSTRACT FROM AUTHOR]

Since an abnormal umbilical cord such as excessive twisting/torsion, cord compression, coiling at the fetal neck are fetal life threatening or restrict fetal growth, it is diagnosed in detail by real time B-mode ultrasound, color Doppler flow mapping, pulsed Doppler flow velocity wave form, ultrasonic fetal monitor and actocardiogram. Abnormality is evaluated by its location, size, twisting and its pitch of the cord, the grade of variable deceleration (VD), non-invasive stress CTG test in maternal movement, RI and PI, absent or reverse flow of end diastole (ARED) of umbilical arterial blood flow velocity wave form, and particularly pulsating blood flow wave of the umbilical vein related to blood stagnation in the vein and pathological vascular changes of the placental villi, fetal and neonatal blood vessels. Its treatment is maternal position change in mild cord compression, while bed rest and total tocolysis is required when the compression signs are heavy in early pregnancy. The fetus is rescued by cesarean section when threatened fetal life is indicated by signs of severe FHR change or ARED with umbilical vein flow pulsation in spite of eager conservative treatment. CNS damage of the neonate, e.g. periventricular leukomalacia (PVL) and hypoxic-ischemic encephalopathy (HIE), is inspected and treated if necessary after cesarean section. [ABSTRACT FROM AUTHOR]